Post by scooter on Aug 29, 2014 6:03:22 GMT -5
With a small engine that runs best in a narrow rpm range like our CVT engines, ideally what want is a tuned length header, (appropriately sized, breathing through a straw is no good), that opens in to an expansion chamber and then necks down and exits to a sound suppressor.
When you get the length and volume of system correct you hit a resonant frequency that matches the exhaust pulses coming out of the engine. Sort of like waves sloshing in a bath tub or a pool. Time the slosh just right and the push/pull will actually help draw more exhaust of out the cylinder. Longer length/more volume/lower rpm and vice versa with shorter/smaller/higher rpm.
